This equipment is used for testing the permeability of granular soils (sands and gravels). The specimen is formed in a permeability cell and water is passed through it from a constant level tank Take-off points located along the sides of the permeability cell are connected to three manometer tubes mounted on a panel complete with a meter scale. Water passing through the specimen is collected and measured, either for a specific quantity or over a period of time. The reduction of head is noted from the variation of water level in the manometer tubes. Comprising three glass tubes of constant bore, meter scale and connecting tubing for cell pressure take-off points, all mounted on a free-standing panel. Manufactured from transparent plastic with attachment for wall mounting. The inlet, outlet and overflow pipes are fitted to the base of the tank and can be adjusted for height within the tank. Supplied complete with connecting tubing. Clays and silts are tested using the falling head technique. Flow of water through the specimen is observed by monitoring the rate of fall of water in the tube. It is essential that soils of very low permeability are sealed inside the cylinder to prevent see page along the sides of the specimen. Before testing, the specimen must be completely saturated with water as the presence of air will restrict the flow of water.